1. Field of the Invention
The present invention relates to an image forming apparatus for recording an image in response to image information on a recording material supplied from a plurality of sheet supply means.
2. Related Background Art
In the past, in image forming apparatuses such as copying machines, as sheet supply means, there have been used a manual insertion sheet supply means in which recording materials (referred to as "sheets" hereinafter) are manually inserted one by one into a manual insertion opening to be supplied to an image forming portion and an automatic sheet supply means in which sheets stacked in a cassette or on a tray are separated one by one and the separated sheet is supplied to an image forming portion. Further, image forming apparatuses having the combination of these sheet supply means have also been usually used.
Now, an example of a conventional copying machine having the above-mentioned manual insertion sheet supply means and automatic sheet supply means will be explained with reference to FIGS. 9 to 11. The copying machine inherently includes the manual insertion sheet supply means and the automatic sheet supply means is added to the machine as an option.
The copying machine includes manual insertion guide members 91 through which a sheet P is supplied by manual insertion, which guide members can be shifted relatively in directions shown by the double headed arrow C to regulate the sheet P in its widthwise direction by their inner guide surfaces 91a, as shown in FIG. 10. A first convey path 92 for guiding the manually inserted sheet P in a direction shown by the arrow A is defined between the manual insertion guides 91. Further, in FIG. 9, there is also provided a second sheet convey path 95 for guiding a sheet P supplied by a sheet convey roller 94 from a cassette 93 mounted within a lower portion of the apparatus in a direction shown by the arrow B.
At a junction between the first and second convey paths 92, 95, a junction guide 96 is integrally formed with a body of the apparatus. The junction guide 96 forms a part of an outer wall of the body of the apparatus. The sheet P conveyed through the first or second convey path 92 or 95 is sent toward the interior of the apparatus by means of a pair of convey rollers 97.
In this way, generally, in the image forming apparatus having both the manual insertion sheet supply means and the automatic sheet supply means, the first convey path 92 for exclusively guiding the sheet supplied by the manual insertion sheet supply means and the second convey path 95 defined by the junction guide 96 and adapted to exclusively guide the sheet supplied by the automatic sheet supply means are dependently formed, so that the sheet P is directed to the pair of convey rollers 97 to be sent to an image forming portion.
However, in the above-mentioned conventional image forming apparatus, it is necessary to previously form the second convey path 95 in the apparatus by using the junction guide 96 and the like. When an electric portion 98 (shown by the two dot and chain line in FIG. 9) is mounted within a lower portion of the apparatus in consideration of compactness of the apparatus, the second convey path 95 does not provide an installation space for the electric portion and the junction guide 96 creates a dead space, thereby reducing the effective installation space for the electric portion in the apparatus.
Further, regarding the above-mentioned image forming apparatus, as shown in FIG. 11, even if the apparatus has the manual insertion sheet supply means alone, as mentioned above, it is necessary to provide the second convey path 95 and an opening 95a therefor. Further, if the automatic sheet supply portion is driven by a drive source of the image forming apparatus, it is also necessary to provide an opening 99 for permitting the drive connection between the automatic sheet supply portion and the image forming apparatus. In this case, there is no problem when the automatic sheet supply portion is integrally mounted to the image forming portion. However, when the image forming apparatus having the manual insertion sheet supply means alone is used independently, there is a danger of foreign matters entering into the apparatus through the openings 95a, 99, thereby causing the malfunction of the apparatus. Further, some modern compact image forming apparatuses must be made to withstand the storage and transportation thereof. In such a case, any members 100 for closing the openings 95a, 99 must be prepared, thereby making the apparatus more expensive.